The term “distal” hereinbelow will always describe the part of the instrument or component, which is located at a distance from the user, the term “proximal” will always describe the part of the instrument or component, which is located closer and which points towards the user.
EP 2 371 316 A1 discloses an electrosurgical instrument for coagulating, sealing and severing biological tissue, such as blood vessels, for example. The instrument encompasses a tool comprising a movable branch, which can be moved towards another branch, so as to seize and clamp the tissue as well as to supply it with current. The tool also includes a blade, which can be moved linearly, so as to sever the sealed tissue. The tool is arranged at the distal end of an elongated shaft, the proximal end of which is held at a housing. The housing encloses an operating drive for the tool and encompasses a handle as well as an operating lever. The operating drive transfers the movement of the operating lever to the tool, so as to close the branches and so as to push the blade forwards. The movement converted by the operating drive is transferred to the tool by means of pull/thrust and sliding elements, which extend through the shaft.
So that the blade executes a straight incision reliably, it must be capable of being operated safely by means of the sliding element, which extends through the shaft. For this purpose, the sliding element must be guided in the shaft, so that it does not evade laterally in response to a translatory motion. However, guidance requires play, so that the sliding element can be operated smoothly. If the sliding element evades the translatory motion laterally, increased friction and inaccurate blade movement can occur in the guidance.